Measure oceanographic currents and
water temperature at this site in Mamala Bay by deploying a
108 m-long mooring outfitted with 4 VACM current meters,
3 temperature probes, and a sediment trap. The data will augment
a data set recently collected and published by the Mamala Bay Study
Commission. The study will provide a more complete understanding
of seasonal variations in oceanographic processes affecting Mamala
Bay. The aim is to determine how the dredged material-- and any
associate pollutants-- might be moved or reworked by oceanographic
processes and redistributed after disposal. This is part of a larger
study that is in its fourth year. The study is designed to assess the
impacts to the seafloor and to benthic invertebrate infauna from the
disposal of harbor dredged material from primarily Pearl and Honolulu
Harbors. Our ultimate goal is to understand the Mamala Bay system
as an urban ocean setting, and to provide Coastal and Urban ocean
managers and policy makers with the information required to make
informed decisions regarding the use of the oceans.

Information to be Derived

Seasonal changes in sediment rate, current speed, temperature, salinity, and
transmissivity at different positions above the seafloor.

Summary

The USGS deployed a 108 m-long mooring on the seafloor at 21.24963
degrees N / 157.87612 degrees W. The site is located immediately east of the old
Honolulu Harbor disposal site, inactive since 1980. The mooring is situated in
about 460 m of water, is 108 m long and outfitted with 4 VACM current meters
(recording speed, direction, temperature, salinity, and transmission), 3
temperature probes located directly below the VACMs, and an Anderson Sediment
trap situated near the middle of the mooring. The sediment trap is outfitted
with an intervalometer so we can assess sedimentation rates. Current meters
are located at about 6 m, 30 m, 40 m, and 100 m above the sea bed. Temperature
probes are located very close to the current meters.